Weight vs. Reps

When following a routine, is it more important to reach the target reps given in the routine or to stay with the weight and until you get to that target rep. For example if the routine says to do 3 sets of 10 reps each and the first 2 sets you were able to use 30lbs and the last set using the same weight only gets you to 8 reps, should I drop weight to reach that 10th rep.

My preference is to stick with that weight and your goal is to get all 3 sets up to 10 reps. Once you reach that goal, you increase weight to knock you back down to 8 reps or so for all 3 sets, then work to increase them all.

That being said, I prefer to work in a rep range, rather than just a target rep. For example, 3 x 8-10 instead of 3x10. That way, I can do my above progression scheme.

when this happens i do a drop set i think its the best thing you can do to push yourself

so for an example your routine would say something like 3 sets 12 reps of bench. by the 3rd set you can only make 8 so what i do is lower the weight as fast as possible and bang out another 5-8 reps... really hits you hard!